1. Field of the Invention
The present invention relates to an electrophotographic photoconductor (hereinafter may be referred to as “photoconductor,” “latent electrostatic image bearing member,” or “image bearing member”) that can provide high-quality image formation and high-speed printing using a spherical toner with a small particle diameter, that can provide an excellent toner recycling efficiency and low-temperature toner fixing properties, that can provide excellent toner cleaning in a low temperature and low humidity environment, that is robust against environmental variability, and that can provide high-quality image formation for a long period of time without involving lubricant application, and an image forming apparatus and process cartridge using the electrophotographic photoconductor.
2. Description of the Related Art
In recent years electrophotographic full-color image formation has been widely used, with a strong demand for high image quality. As a strategy for meeting such a demand it is known to use a spherical toner with a uniform, small particle diameter that can significantly enhance fine-dot reproducibility. The production of such a toner has been realized through polymerization processes, and spherical toners with a small particle diameter have been commonly used.
As a method for cleaning transferred toner particles remained on the photoconductor in an electrophotographic image forming apparatus, a blade cleaning method is widely used that involves contact between a cleaning blade and a photoconductor for toner cleaning. Although this method is most suitable particularly in high-speed printing machines, there is a problem that small, spherical toner articles offer poor cleanability with a blade. To solve this problem, application of a lubricant on the photoconductor has been carried out for improving cleanability. However, since lubricants degrade chargeability of recovered toner particles by being mixed with them, they cause difficulties in toner recycling.
In addition, environment impact reduction has also been a highly marketable requirement and it has been desired to lower the fixing temperature in an electrophotographic image forming apparatus. To that end, it is effective to lower the glass transition temperature of toner. As a method for producing a spherical toner having a uniformly, small particle diameter and a low glass transition temperature, Japanese Patent Application Laid-Open (JP-A) No. 2003-202701 discloses a method that includes the steps of dispersing in an aqueous medium a modified polyester resin that is reactive with an active hydrogen group-containing compound, a coloring agent, and a releasing agent under the presence of a dispersing agent, allowing the obtained dispersion liquid to react with at least one of a crosslinking agent and an elongating agent, and removing a solvent from the dispersion liquid.
However, a toner produced by this proposed method has a spherical shape with a uniform, small particle diameter. Thus the toner is hardly removed by blade cleaning, particularly in a low temperature and low humidity environment, making it difficult to achieve image output without lubricant application.